Technical Field
This disclosure generally relates to grinding mechanisms, and more particularly to grinders or mills with high speed and adjustable grinding mechanisms for grinding materials, such as spices and grains.
Description of the Related Art
Traditional spice and grain mills are common household and kitchen tools. They often comprise a hollow cylindrical body with a grinding rasp and rasp ring at one end and a grind knob at the other. A grinder shaft typically runs along the central axis of the body and connects the rasp and knob together such that a user may hold the body and turn the knob, causing the rasp to rotate relative to the rasp ring and grind the material contained within the body. Most mills also provide a means for adjusting the grind coarseness between fine and coarse settings.
The means for adjusting the grind is usually an additional knob threaded onto an extreme end of the grinder shaft, either at the top, above the grind knob, or at the bottom, below the grinding rasp. In either case, to adjust the grind setting, a user must adjust their hold on the grinder, reposition their hands to grab the grind adjustment knob, and tighten or loosen the knob. The knob is usually a small nut that requires fine motor skill to adjust. In the case of a bottom mounted grind adjustment knob, the user's fingers usually get covered in spice or grain dust that may accumulate at the outlet of the mill. Once the user has adjusted the grind they must reposition their hands again before they resume grinding. If the grind needs additional adjustment, then the user must interrupt the grinding process again, reposition their hands, and make further adjustments with the grind adjustment knob. This traditional method for adjusting the grind coarseness is awkward and time consuming.
In existing mills, the turn handle or knob the user turns to grind the material connects directly to a shaft and the shaft then connects to a rasp such that for every rotation of the knob or handle, the rasp completes one rotation. In an effort to reduce the force necessary for grinding material, some mills include handles offset from the axis of rotation of the grind shaft, creating a lever arm and increasing the torque delivered to the grinder. Gear mechanisms have also been developed to increase the torque to the grinder. These gear mechanisms slow the grinding process because they reduce the output speed of the grinder such that a single rotation of the turn knob or handle causes less than one rotation of the rasp.
It is desirable to have a mill that allows for a simple, easy, and straightforward grind adjustment. Further, it is desirable to have a mill with a grind adjustment mechanism that does not require the user to significantly reposition their hands to change the grind setting. In addition, it is desirable to have a mill that quickly grinds spices and grains with a grinding mechanism that makes more than one rotation for each rotation of a turn knob or handle.